Fix #2115

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -811,5 +811,10 @@ Thibaut Robert (trobert@github)
   * Requested #2059: Remove `final` modifier for `TypeFactory`
   (2.10.0)
 
+Christopher Smith (chrylis@github)
+  * Suggested #2115: Support naive deserialization of `Serializable` values as "untyped",
+    same as `java.lang.Object`		     
+  (2.10.0)
+
 Édouard Mercier (edouardmercier@github)
   * Requested #2116: Make NumberSerializers.Base public and its inherited classes not final

release-notes/VERSION-2.x

@@ -8,6 +8,9 @@ Project: jackson-databind
 
 #2059: Remove `final` modifier for `TypeFactory`
  (requested by Thibaut R)
+#2115: Support naive deserialization of `Serializable` values as "untyped", same
+  as `java.lang.Object`
+ (requested by Christopher S)
 #2116: Make NumberSerializers.Base public and its inherited classes not final
  (requested by Édouard M)
 

src/main/java/com/fasterxml/jackson/databind/deser/BasicDeserializerFactory.java

@@ -1,5 +1,6 @@
 package com.fasterxml.jackson.databind.deser;
 
+import java.io.Serializable;
 import java.util.*;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicReference;
@@ -8,8 +9,10 @@
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonCreator.Mode;
+
 import com.fasterxml.jackson.core.JsonLocation;
 import com.fasterxml.jackson.core.JsonParser;
+
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.cfg.DeserializerFactoryConfig;
 import com.fasterxml.jackson.databind.cfg.HandlerInstantiator;
@@ -46,6 +49,7 @@ public abstract class BasicDeserializerFactory
     private final static Class<?> CLASS_CHAR_SEQUENCE = CharSequence.class;
     private final static Class<?> CLASS_ITERABLE = Iterable.class;
     private final static Class<?> CLASS_MAP_ENTRY = Map.Entry.class;
+    private final static Class<?> CLASS_SERIALIZABLE = Serializable.class;
 
     /**
      * We need a placeholder for creator properties that don't have name
@@ -1771,8 +1775,8 @@ public JsonDeserializer<?> findDefaultDeserializer(DeserializationContext ctxt,
         throws JsonMappingException
     {
         Class<?> rawType = type.getRawClass();
-        // Object ("untyped"), String equivalents:
-        if (rawType == CLASS_OBJECT) {
+        // Object ("untyped"), and as of 2.10 (see [databind#2115]), `java.io.Serializable`
+        if ((rawType == CLASS_OBJECT) || (rawType == CLASS_SERIALIZABLE)) {
             // 11-Feb-2015, tatu: As per [databind#700] need to be careful wrt non-default Map, List.
             DeserializationConfig config = ctxt.getConfig();
             JavaType lt, mt;
@@ -1785,6 +1789,7 @@ public JsonDeserializer<?> findDefaultDeserializer(DeserializationContext ctxt,
             }
             return new UntypedObjectDeserializer(lt, mt);
         }
+        // String and equivalents
         if (rawType == CLASS_STRING || rawType == CLASS_CHAR_SEQUENCE) {
             return StringDeserializer.instance;
         }

src/main/java/com/fasterxml/jackson/databind/deser/std/StdKeyDeserializer.java

@@ -1,6 +1,7 @@
 package com.fasterxml.jackson.databind.deser.std;
 
 import java.io.IOException;
+import java.io.Serializable;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.net.MalformedURLException;
@@ -72,9 +73,13 @@ public static StdKeyDeserializer forType(Class<?> raw)
         int kind;
 
         // first common types:
-        if (raw == String.class || raw == Object.class || raw == CharSequence.class) {
+        if (raw == String.class || raw == Object.class
+                || raw == CharSequence.class
+                // see [databind#2115]:
+                || raw == Serializable.class) {
             return StringKD.forType(raw);
-        } else if (raw == UUID.class) {
+        }
+        if (raw == UUID.class) {
             kind = TYPE_UUID;
         } else if (raw == Integer.class) {
             kind = TYPE_INT;

src/main/java/com/fasterxml/jackson/databind/deser/std/StdKeyDeserializers.java

@@ -48,9 +48,7 @@ public static KeyDeserializer constructDelegatingKeyDeserializer(Deserialization
     public static KeyDeserializer findStringBasedKeyDeserializer(DeserializationConfig config,
             JavaType type)
     {
-        /* We don't need full deserialization information, just need to
-         * know creators.
-         */
+        // We don't need full deserialization information, just need to know creators.
         BeanDescription beanDesc = config.introspect(type);
         // Ok, so: can we find T(String) constructor?
         Constructor<?> ctor = beanDesc.findSingleArgConstructor(String.class);

src/test/java/com/fasterxml/jackson/databind/deser/jdk/UntypedDeserializationTest.java

@@ -9,6 +9,7 @@
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
 import com.fasterxml.jackson.core.*;
+import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.ObjectMapper.DefaultTyping;
 import com.fasterxml.jackson.databind.deser.ContextualDeserializer;
@@ -114,6 +115,11 @@ static class WrappedUntyped1460 {
         public Object value;
     }
 
+    // [databind#2115]
+    static class SerContainer {
+        public java.io.Serializable value;
+    }
+
     /*
     /**********************************************************
     /* Test methods
@@ -383,4 +389,25 @@ public void testUntypedIntAsLong() throws Exception
                 .readValue(JSON);
         assertEquals(Long.valueOf(3), w.value);
     }
+
+    // [databind#2115]: Consider `java.io.Serializable` as sort of alias of `java.lang.Object`
+    // since all natural target types do implement `Serializable` so assignment works
+    public void testSerializable() throws Exception
+    {
+        final String JSON1 = aposToQuotes("{ 'value' : 123 }");
+        SerContainer cont = MAPPER.readValue(JSON1, SerContainer.class);
+        assertEquals(Integer.valueOf(123), cont.value);
+
+        cont = MAPPER.readValue(aposToQuotes("{ 'value' : true }"), SerContainer.class);
+        assertEquals(Boolean.TRUE, cont.value);
+
+        // But also via Map value, even key
+        Map<?,?> map = MAPPER.readValue(JSON1, new TypeReference<Map<String, Serializable>>() { });
+        assertEquals(1, map.size());
+        assertEquals(Integer.valueOf(123), map.get("value"));
+
+        map = MAPPER.readValue(JSON1, new TypeReference<Map<Serializable, Object>>() { });
+        assertEquals(1, map.size());
+        assertEquals("value", map.keySet().iterator().next());
+    }
 }

src/test/java/com/fasterxml/jackson/databind/module/TestAbstractTypes.java

@@ -77,7 +77,7 @@ public String getValue() {
             return value;
         }
     }
-    
+
     /*
     /**********************************************************************
     /* Test methods
@@ -157,7 +157,7 @@ public void testInterfaceDefaulting() throws Exception
     }
 
     // [databind#2019]: mappings from multiple modules
-    public static void testAbstractMappingsFromTwoModules() throws Exception
+    public void testAbstractMappingsFromTwoModules() throws Exception
     {
         ObjectMapper mapper = newObjectMapper();
         SimpleModule module1 = new SimpleModule("module1");